In terms of ecological and environmental problems caused by human activities, changes in the pattern of land use play a decisive role in regional eco-security. In recent years, ecological considerations have been an important limiting factor and optimization goal, with the concept of eco-security reflected in land use pattern optimization. Supported by 3S technology, we chose the Huangfuchuan watershed of the Yellow River basin as the study area-a rare, sandy, gritty, intense erosion area of the world, where soil erosion and ecological water are important factors determining regional eco-security. Here we carried out comprehensive research that involved the monitoring and forecasting of change in land use, soil erosion simulation, estimation of appropriate vegetation coverage, and optimization of land use. The results were as follows. (1) Over the last 10 years, there has been a general change in land use in the Huangfuchuan watershed, with the proportion of construction land, woodland, cropland and shrub increasing gradually over time (although the rate of increase has slowed), and the proportion of water, grassland, sand and bare rock decreasing, most markedly in water resources. During this course of development, the watershed pattern of land use has been under tremendous pressure from the conflict between rapid urbanization, economic development and the conservation and rebuilding of the ecological environment. This scenario looks set to continue for some time in the future, and moreover, the distinct decline in water area would be the main obstacle in the above conflict. (2) Change in the pattern of land use was an important factor in the course of soil erosion, the annual modulus of soil erosion decreased rapidly from 16160.72 t/km² in 1987 to 9710.72 t/km² in 2015. To a degree, soil erosion was closely related to type of land use. According to the annual modulus of soil erosion in the same year, different types of land use impacted on soil erosion with the following order of magnitude: bare rock > sand > cropland > grassland > woodland > shrub, indicating that woodland and shrub were the preferred measures for vegetation restoration and a reduction in soil erosion. Furthermore, the alteration of sand and bare rock would be critical to the comprehensive control of soil erosion, a fact that could not be ignored. (3) The effect of soil and water conservation has been significant over the last 10 years; however, owing to the high proportion of sand and bare rock and the proliferating cropland in the watershed, the annual modulus of soil erosion remained higher than the permissible degree of soil erosion, namely 5300 t/km². Land use pattern optimization can help to improve ecosystem services in the Huangfuchuan watershed, and achieve the goal of promoting eco-security. After optimization, the annual modulus of soil erosion could decrease by 5469.57 t/km² and 5432.77 t/km² in 2007 and 2015, with 4277.95 t/km² in 2015, which is considerably below the permissible degree of soil erosion. Generally, our paper has emphasized the impact of different types and patterns of land use on soil erosion, highlighted the adjustment or optimization in pattern of land use, and suggested improvements in the scientific assessment of soil erosion for the simulation and forecasting of land use change, which has broad future applications.